Several dinosaurs have been dug up in Arizona. That includes the first Dilophosaurus (of Jurassic Park fame), as well as one of the oldest dinosaurs ever discovered, believed to be 225 million years old. Up in Tuba City, you can actually see dinosaur tracks.

The Hohokam were the only culture in North America to rely on irrigation canals to supply water to their crops. In the arid desert environment of the Salt and Gila River Valleys, the homeland of the Hohokam, there was not enough rainfall to grow crops. To meet their needs, the Hohokam engineered the largest and most sophisticated irrigation system in the Americas.

Other canal systems found around Arizona have given clues about civilizations even older than the Hohokam.

The Grand Canyon is a natural scientist's dream come true. There are more than 373 bird species, 89 mammal species, 47 reptile species, 9 amphibian species, and 17 fish species. There are more than 1,700 known species of plants, along several different ecosystems.

It's "one of the most studied geologic landscapes in the world," according to the National Park Service.

"Its great biological diversity can be attributed to the presence of five of the seven life zones and three of the four desert types in North America," according to the Park Service. "The five life zones represented are the Lower Sonoran, Upper Sonoran, Transition, Canadian, and Hudsonian. This is equivalent to traveling from Mexico to Canada."